Yes. My main supermarket (a former Safeway in the UK) has one person looking after 20 self-checkout stations. I guess most of us have learned the system by now.....

Self-checkout works well for half a dozen items in a hand basket. If you have a trolley full of a week's shopping, you're going to use a cashier. In fact, in this supermarket, you can't even get a trolley into the self-checkout area.

My local M&S store has three different checkout areas. (1) traditional, for people with trolleys. (2) Self-checkout area for people with baskets. (3) Really fast (but very narrow) lane for people just holding a few items in their hands. You almost never see people using the "wrong" area.

What's interesting is that I usually pick the one with the longest queue, ie line 3. The cashiers are really fast so you don't have to wait long.

One other factor is that a lot of us in line 3 are using contactless (Wave & Pay) cards, so the payment process doesn't slow things down. People who don't usually use the waiting time to get their cash ready.

In our local stores in the USA, its one person looking after 4 or 6 stations, 2 or 3 of which are perpetually out of service.

Same. It seems that this is just a temporary and fragile step toward something else. Amazon Go or else.

Maybe an early adopter problem, unless they've upgraded the checkout stations to current technologies? The UK ones are mostly quite recent seem to work fine (though I have no experience outside London).